Bad Cylinder on Expedition. What to do?

[TD_Maker]

The 5.4 Litre Engines = Nightmares in some situations. I had the identical power plant in my 2006 F150 . I would say there is very little chance that your misfire is coming from bad piston rings. Your engine has 8 separate coil packs---one for each cylinder. I will bet one of those coils are bad causing a misfire...and it may be an intermittent thing too. Are you getting a check engine light? if so, take it to Auto Zone and get a reading. Often, a reading can pin point exactly which cylinder is misfiring.

Now, this engine is famous for spark plug issues as well. The factory two piece spark plugs are famous for breaking off in the cylinder head during the removal process (In fact, there is a Ford Service bulletin addressing this exact issue) If by chance you are considering changing the plugs, follow the service bulletin EXACTLY before attempting to remove the plugs. Make sure you have read numerous articles and watched the available YouTube videos on this exact situation. It can be a nightmare if the plugs break off. In fact, I off broke 6 of 8 plugs when I attempted mine. If you are unlucky enough to break off the #4 or #7 or #8 cylinder plugs, these are a real issue to remove.

I visited a local Ford dealer to ask for help or suggestions on this issue. The service manager took me in the work bay area and showed me an Expedition with the entire body removed from the chassis. The removal was required to gain access to the cylinder heads because of the broken spark plugs still inside. He told me this was a $4000 job.

Get a second opinion....maybe a third. You make get lucky

 

[bruceb58]

TD. You need to read the whole thread. Dealer had to take spark plugs out to do compression checks.

 

[bruceb58]

Coop, did your dealer happen to mention this TSB?
http://motrolix.com/2014/06/ford-is...igators-expeditions-mark-lt-and-f-150-trucks/

 

[lncoop]

I was continuing the endless Googling last night and after seeing Just Answer for the 800th time I clicked on it for giggles and was connected to an extremely knowledgeable Ford expert with whom I had a long and enlightening conversation. He suspects a fuel injector leak down. It's a known problem that carries an additional eleven year/120k mile warranty from Ford. He believes the injector probably leaked down and washed the cylinder wall thereby causing the stuck rings. The PO had 7, 8 and 9 done at 50k miles. I'm past the warranty by 1500 miles but he was optimistic the dealer would assist me with it especially since I've already paid them five bills for essentially useless diagnostics. He said they absolutely should have mentioned it and even told me the prescribed test for the issue and where to tell them to access the info. This could have ended very badly. He also recommended letting a little tranny fluid sit in the cylinder for a day to reseat the rings. I'm waiting on the service manager to call me now.

 

[bruceb58]

4% compression difference should not cause a rough idle, especially something that happened suddenly like yours.

Very easy to test for a leakdown with a fuel pressure gauge. You can buy them very inexpensively at Harbor Freight.

 

[Scott Danforth]

Also clean the MAF makes a big difference.

This is in a little-known service bulletin covering many rough running fords with the modular based engines. dust and pollen that makes it thru the air filter burns itself onto the MAF sensor wire. a shot of electric contact cleaner will take care of it.

 

[Tail_Gunner]

5.4 V8. They did perform leak down and determined rings. Haven't asked about codes but the CEL never illuminated. It just started idling rough last night and when I started it this morning it sounded a little noisier than usual which is saying a lot. That's a chattery engine.

Take a very close look at your injector rail's Ford's are quite noisy...extra clatter bad injector highly likely. You can do something as simple as taking a engine stethascope and place it or each injector and listen to them bang....

 

[lncoop]

Well, it's been a while so I thought I'd update you guys with basically no new info. I had another conversation with the service adviser at the dealership and asked him specifically about the injector leak down issue. He promised me they checked the warranty history and followed Ford's diagnostic procedures for that and would have replaced the injector under warranty (even though I'm out) had that been the issue. I told him if that did turn out to be the issue and resulted in catastrophic failure we would have a big problem. He agreed. What else could either of us say? (FWIW I've used these guys several times and have never had any problems with them.) I haven't had any performance issues since; no more rough idle and still no CEL. The only thing I've observed is a slight but noticeable increase in the noise I've always attributed to the cam phasers. Is it that or something else? I don't know.:noidea: Nor does anyone else apparently. I don't mind some noise in a ten year old engine provided it doesn't affect performance or signal a major problem that needs attention. I just don't want something to let go at 2k RPMs in the middle of nowhere with a truck full of gear and the vice admiral, boats on the roof and a trailer on the back.

After talking with the dealer again I called a local engine shop and told him everything. He said the misfire code and rough idle could have been caused by anything and to bring it in if I wanted but recommended I just drive it as long as I wasn't having any more performance issues. At this point that's all I know to do unless whatever issue I may or may not have gets bad enough to diagnose. I reckon the worst case scenario is eventual engine rebuild or replacement which I've priced at $4500, which would be less than a year's payments on a new one.

If anyone wants to take a crack at this and needs a complete recap I'm happy to oblige. Otherwise, https://www.youtube.com/watch?v=Otm4RusESNU